Tumour treatment, e.g. with chemotherapeutic drugs, often leads to a rapid loss of strength in patients and increases their cardiovascular risk and general mortality. Accompanying physical training can mitigate these effects.
Chemotherapy puts a lot of stress on the body of cancer patients. Fatigue is often observed. Blood values change and the body can have increasing difficulties with the oxygen supply in the periphery. Many chemotherapeutic drugs also have a cardiotoxic effect - cardiovascular risk increases and, according to recent studies, can often rise years after tumor therapy.
Cardiorespiratory fitness (CRF) is an important measure for assessing the fitness of cancer patients before, during, and after treatment. It indicates how well the body is able to deliver oxygen to the successful organs, the muscles, under stress. Metabolic equivalents of task (MET) also play a role. This value is the quotient of working energy consumption divided by resting energy consumption.
It is already known from studies that increasing the MET value in patients can reduce the cardiotoxic effects of chemotherapy and thus also reduce the risk of subsequent events. For each increase of +1 MET, the cardiovascular risk of patients decreases by about 15% and overall mortality by about 13%. In general, the higher the CRF and MET values of the patients, the better the overall result of the treatment.
Lack of fitness before cancer therapy is one side of the coin. In many cases, however, it is also the case that cancer and its treatment cause CRF and MET to drop even further. Studies in mice and breast cancer patients have shown that in the opposite case, such effects can be reduced by supportive training.
For example, training in mice prevented some chemical agents from causing severe toxicity. In women with breast cancer, it was also observed that the risk of cardiovascular events decreased as the level of training increased.
According to current knowledge, the effects of training are measurable but comparatively small and should always be seen in conjunction with other factors, such as diet, smoking status, etc.
Nevertheless, CRF is considered a good predictor of cardiovascular mortality, cancer mortality, and all-cause mortality. It is important to note that the CRF is often reduced for years among cancer survivors. This is mainly due to the toxicity of tumor therapy and related deconditioning.
On the other hand, accompanying training reduces cardiovascular and mortality risks. In cardiovascular-oncological rehabilitation, personalized approaches are offered not least through adapted training.
Barac A. Physical training to prevent cardiotoxicity of cancer therapy. In: Expert Advice - Cardiotoxicity of Cancer Therapy, ESC 2020